In medicine, veins are deliberately perforated by needles (venepuncture) for a variety of reasons and by a variety of persons who differ in their skills and the time available to attend to the wound site after the needle is withdrawn. A laboratory technician has to take blood samples from a large number of patients on a routine basis; an anaesthetist has to continue anaesthesia after giving a sleep-inducing injection. Both may have little time available to ensure pressure is maintained on the venepuncture site.
If pressure is not applied and blood is permitted to leak from a venepuncture site the area may become painful, bruised and therefore unsightly, or swollen due to a mass of solid blood (haematoma) forming. There may be dangerous blood volume loss in small patients. Pressure on and thrombosis of the vein can occur, rendering the vessel unusable, and this can be dangerous in life-threatening situations. When patients are being treated with anti-clotting agents, even greater care must be taken to exert pressure and ensure that bleeding does not occur.
In present practice there are at least eight varying ways of attempting to prevent bleeding following venepuncture. This indicates that none is totally satisfactory. Most utilise the attendant's time and are therefore inefficient. Some do not attempt to maintain pressure whilst some that do fail. Some dressings are clumsy in their construction. Some require the assistance of the patient or another attendant to be effective. Many are expensive to manufacture.
In general, a medical attendant should hold in one hand either the needle itself or a syringe to which the needle is attached prior to removal of the same. At this time the attendant needs to be able with the other hand to pick up a surgical dressing on which no time has been spent in prior preparation, and apply it immediately in an aseptic state directly and under pressure over the puncture site. This having been accomplished the needle is removed and within a few seconds the dressing must be fixed so that, without any external agency, it maintains firm pressure on the wound and prevents bleeding.
In greater detail, what is required in an aseptic surgical pressure dressing is the following:
1. It should be simple in both structure and application so that its manner of use is quickly understood by the thousands of medical attendants who would use it every day and so that manufacture would be no overriding problem.
2. Speed of application should be permitted by its simplicity of design, to permit effective blood sampling.
3. The dressing should be pressure effective, until complete haemostasis is achieved which occasionally may require that the dressing should remain not only effective in situ for 30 minutes or longer but also remain effective:
(i) at all possible anatomical venepuncture sites, e.g. the bend at the elbow (the cubital fossa) which presents a valley of varying depth; the pressure exerted must be effective on the floor of this area. PA1 (ii) with all age groups, including those elderly patients whose subcutaneous tissues are occasionally very lax and induce a certain loss in tension in tapes after they have been pulled over central pads. PA1 (iii) on a wide variety of sizes of puncture wound left by the needles of widely varying size which have penetrated the skin at an angle to the skin surface.
4. It should be possible to apply the dressing without the need for assistance either from the patient or another attendant. It should therefore be capable of being effectively employed in all hospital treatment areas without affecting hospital operating efficiency deleteriously.
5. The dressing should be absorbent. Effective pad pressure will prevent blood loss from the venepuncture wound but on removal of the needle a thin bloody tail is often left where the needle passes between pad and skin. Aesthetically, this blood is preferably absorbed into the dressing pad.
6. The size of the dressing should be similar to that of standard plasters, e.g. "Band-aids" (Registered Trade Mark). This is for aesthetic and comfort reasons.
7. The dressing should be non-allergenic so as not to cause local and/or generalised skin irritant rashes of true allergic character.